Hey dude, it's me.
I don't have time at the moment to look at the API in detail, but one simple way to do this would be to make a holder page type for the dates. You'll be creating an extra layer of depth in the content tree, but you'll be able to organize your pages easily by 'date' simply using the Children methods already defined in the controller. Very roughly, without code, something like:
Site
-> News (ArticleDateHolder)
->-> October 1, 2008 (ArticleHolder)
->->-> Article 1 (Article)
->->-> Article 2 (Article)
->->-> Article 3 (Article)
->-> October 2, 2008 (ArticleHolder)
->->-> Article 1 (Article)
->->-> Article 2 (Article)
->->-> Article 3 (Article)
If you prefer to just add articles without the extra layer, let me know and I'll take a closer look at the API so that I can figure out the best way to query for results. Off the top of my head, I think you'll want to nest two controller methods in the .ss file, one that pulls unique records based on date (one record for each unique date), then another that pulls records based on each date. Obviously these methods need to be defined in the .php file. The .ss template might look something like this (again, very roughly):
<% control GetUniqueDates %>
<span class="newsDateTitle">$Date.Format(m.d.Y)</span><br/>
<% control GetArticlesByDate(Date) %>
<div class="newsItem">
<h5><a href="$Link" title="Read more on "{$Title}"">$Title</a></h5>
<span class="newsSummary">$Content.FirstParagraph <a href="$Link" title="Read more on "{$Title}"">Read more >></a></span>
</div>
<% end_control %>
<% end_control %>
Hope this helps. Again, I can try to take a closer look at the API in order to help you with the controller methods, if you decide to continue with the second (and perhaps more reasonable) option. Also, I just bought a guitar, and am going to start taking some lessons here.